1. Field of the Invention
The present invention relates to a pressure detector for detecting the pressure of a fluid that flows through the interior of a flow passage.
2. Description of the Related Art
Heretofore, for example, in a manufacturing process for semiconductor manufacturing or the like, liquids consisting of chemicals and pure water or the like are used, and a pressure detector is connected with respect to tubes through which such liquids are made to flow, whereby measurement of the pressure of the liquid that flows through the interior of the tubes is carried out by the pressure detector.
As one type of such a pressure detector, for example, as disclosed in Japanese Laid-Open Patent Publication No. 11-512827 (PCT) (Patent Document 1), a disk membrane is provided between an internally disposed pressure sensor, which is connected with respect to a fluid flow circuit through which a corrosive liquid flows, and a hole portion that the corrosive liquid flows into, whereby the pressure sensor is separated from and is prevented from coming into direct contact with the corrosive liquid. In this case, a fluid pressure, which is transmitted through the disk membrane, is detected by the pressure sensor.
Further, in Japanese Laid-Open Patent Publication No. 09-166512 (Patent Document 2), a fluid pressure sensor is disclosed in which the pressure sensor is built into the interior of a tube fitting, and the pressure sensor is separated from the fluid by a diaphragm, which is disposed between the pressure sensor and a flow passage through which the pressure fluid flows.
Furthermore, in the pressure sensor disclosed in Japanese Laid-Open Patent Publication No. 2005-207946 (Patent Document 3), a recessed upper surface is provided, which is located at an intermediate portion of a flow passage connected between an upstream side connection port and a downstream side connection port, and fluid pressure measurement is carried out by arranging the pressure receiving surface of a sensor main body so as to face an opening of the flow passage, which opens at a top part of the recessed upper surface.